Messages in this thread | | | From | "Song Bao Hua (Barry Song)" <> | Subject | RE: [PATCH v3 1/2] dma-direct: provide the ability to reserve per-numa CMA | Date | Thu, 23 Jul 2020 12:08:27 +0000 |
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> -----Original Message----- > From: Christoph Hellwig [mailto:hch@lst.de] > Sent: Friday, July 24, 2020 12:01 AM > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com> > Cc: Christoph Hellwig <hch@lst.de>; m.szyprowski@samsung.com; > robin.murphy@arm.com; will@kernel.org; ganapatrao.kulkarni@cavium.com; > catalin.marinas@arm.com; iommu@lists.linux-foundation.org; Linuxarm > <linuxarm@huawei.com>; linux-arm-kernel@lists.infradead.org; > linux-kernel@vger.kernel.org; Jonathan Cameron > <jonathan.cameron@huawei.com>; Nicolas Saenz Julienne > <nsaenzjulienne@suse.de>; Steve Capper <steve.capper@arm.com>; Andrew > Morton <akpm@linux-foundation.org>; Mike Rapoport <rppt@linux.ibm.com>; > Zengtao (B) <prime.zeng@hisilicon.com>; huangdaode > <huangdaode@huawei.com> > Subject: Re: [PATCH v3 1/2] dma-direct: provide the ability to reserve > per-numa CMA > > On Wed, Jul 22, 2020 at 09:41:50PM +0000, Song Bao Hua (Barry Song) > wrote: > > I got a kernel robot warning which said dev should be checked before > > being accessed when I did a similar change in v1. Probably it was an > > invalid warning if dev should never be null. > > That usually shows up if a function is inconsistent about sometimes checking it > and sometimes now. > > > Yes, it looks much better. > > Below is a prep patch to rebase on top of:
Thanks for letting me know.
Will rebase on top of your patch.
> > --- > From b81a5e1da65fce9750f0a8b66dbb6f842cbfdd4d Mon Sep 17 00:00:00 > 2001 > From: Christoph Hellwig <hch@lst.de> > Date: Wed, 22 Jul 2020 16:33:43 +0200 > Subject: dma-contiguous: cleanup dma_alloc_contiguous > > Split out a cma_alloc_aligned helper to deal with the "interesting" > calling conventions for cma_alloc, which then allows to the main function to > be written straight forward. This also takes advantage of the fact that NULL > dev arguments have been gone from the DMA API for a while. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > kernel/dma/contiguous.c | 31 ++++++++++++++----------------- > 1 file changed, 14 insertions(+), 17 deletions(-) > > diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c index > 15bc5026c485f2..cff7e60968b9e1 100644 > --- a/kernel/dma/contiguous.c > +++ b/kernel/dma/contiguous.c > @@ -215,6 +215,13 @@ bool dma_release_from_contiguous(struct device > *dev, struct page *pages, > return cma_release(dev_get_cma_area(dev), pages, count); } > > +static struct page *cma_alloc_aligned(struct cma *cma, size_t size, > +gfp_t gfp) { > + unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT); > + > + return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN); > +} > + > /** > * dma_alloc_contiguous() - allocate contiguous pages > * @dev: Pointer to device for which the allocation is performed. > @@ -231,24 +238,14 @@ bool dma_release_from_contiguous(struct device > *dev, struct page *pages, > */ > struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) > { > - size_t count = size >> PAGE_SHIFT; > - struct page *page = NULL; > - struct cma *cma = NULL; > - > - if (dev && dev->cma_area) > - cma = dev->cma_area; > - else if (count > 1) > - cma = dma_contiguous_default_area; > - > /* CMA can be used only in the context which permits sleeping */ > - if (cma && gfpflags_allow_blocking(gfp)) { > - size_t align = get_order(size); > - size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); > - > - page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN); > - } > - > - return page; > + if (!gfpflags_allow_blocking(gfp)) > + return NULL; > + if (dev->cma_area) > + return cma_alloc_aligned(dev->cma_area, size, gfp); > + if (size <= PAGE_SIZE || !dma_contiguous_default_area) > + return NULL; > + return cma_alloc_aligned(dma_contiguous_default_area, size, gfp); > } > > /** > -- > 2.27.0
Thanks Barry
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